Generally, vehicle seats are formed with standard structures so that various components for driver convenience can be selectively installed in vehicles without having to change vehicle seat frames. Vehicle seats are required to satisfy legal strength requirements, and since a driver operates a car while sitting on a vehicle seat, the vehicle seat is a part directly affecting ride quality.
Referring to FIG. 1, a vehicle seat (1) of the related art is manufactured by machining a steel plate at room temperature to form individual components and assembling the individual components by welding. Alternatively, as shown in FIG. 2, components are formed by die casting using magnesium, the density of which is about ⅕ the density of steel, and the components are assembled using bolts to form a light seat frame (2). The density of steel is about 7.8 g/cm3, while the density of magnesium is about 1.74 g/cm3.
Vehicle seats must satisfy strength requirements for safety. However, magnesium die-cast components are vulnerable to shearing due to the inevitable properties of magnesium, and impurities, such as oxides and die-casting defects such as pores, may weaken magnesium die-cast components. Thus, magnesium die-cast component joint portions are generally designed to be five or more times thicker than comparable steel component joint portions.
As a result, even in the case that the density of magnesium is about ⅕ the density of steel, a seat frame formed by die casting using magnesium may be only be lighter than a corresponding steel frame by about 2 kg or less, only resulting in about 10% or less weight reduction.
In addition, for example, when a vehicle travels over a speed bump or drives on an uneven road, the vehicle may be strongly impacted to make a cushioning frame vibrate vertically or a seat back frame vibrate backwards and forwards. If a vehicle is subjected to such strong vibrations for an extended period of time, magnesium die-cast components, the properties of which are not uniform, may be significantly damaged and cracked. Thus, magnesium die-cast components should be sufficiently thick to absorb external impacts.
In addition, when a driver operates a vehicle for a long time, the driver may be subjected to excessive vibrations through a seat frame and may become less alert due to accumulated fatigue, possibly resulting in an accident. In addition, excessive vibrations may significantly reduce driving comfort and stability and make it difficult to satisfy current customer demands for luxurious driving functions. Thus, the value of a vehicle may be reduced.
Although steel seat frames, which are widely used, are strong and safe, such steel seat frames easily transmit impacts or vibrations and have low vibration dampening abilities, due to their high spring constants. If vibration dampers are added to compensate for the low vibration dampening abilities of steel seat frames, the weight thereof may be increased.
An aspect of the present invention provides a vehicle seat component formed of a magnesium plate to remove limitations on a vehicle seat formed by magnesium die casting.
Another aspect of the present invention provides a vehicle seat structure that is lighter than a steel vehicle seat structure, while providing the same function thereof.
Another aspect of the present invention provides a vehicle seat structure that can provide user comfort by rapidly absorbing vibrations, generated in a vehicle-moving direction, and that is not excessively deformed even when a vehicle collides with another object, such that a user can be safely protected.
Another aspect of the present invention provides a vehicle seat structure including a magnesium plate component and an impact control component attached to the magnesium plate component to absorb or distribute impact energy while being deformed. Thus, according to the present invention, stable, light vehicle seats can be provided to a vehicle to allow for high fuel efficiency.